Fix for issue #120

<pathelement location="${basedir}/build/tools/ant-contrib-1.0b3.jar"/>

to:

<pathelement location="${basedir}/ant-build-script/tools/ant-contrib-1.0b3.jar"/>

This was changed b/c the build script was failing. It was looking for ant-contrib-1.0b3.jar in the 'build' folder which does not exist.